Roofing products are often divided into three broad groups: shingles, roll roofing, and underlayment. Shingles and roll roofing typically function as outer roof coverings designed to withstand exposure to weather and the elements. Shingles and roll roofing generally contain the same basic components which provide protection and long term wear associated with asphalt roofing products. These components include a base material made from an organic felt or fiberglass mat which serves as a matrix to support the other components and gives the product the required strength to withstand manufacturing, handling, installation and service in the intended environment. An asphalt coating formulated for the particular service application is often applied to the base material to provide the desired long-term ability to resist weathering and to provide stability under temperature extremes. An outer layer of mineral granules is also commonly applied to the asphalt coating to form a surface exposed to the weather which shields the asphalt coating from the sun's rays, adds color to the final product and provides fire resistance.
Typically, shingles are installed on a roof deck such that the shingles are in a row from left to right and the lateral edges of the shingles in the row are contiguous with each other so as to abut each other, i.e. their lateral edges are adjacent to one another. Each row represents a course and the shingles are applied in overlapping courses on the roof deck, wherein the buttlap portion of a subsequent course is placed on the headlap portion of a previous course. The headlap portion of a conventional shingle is at least as wide as the buttlap portion of the shingle so that when the shingles are installed on a roof deck in overlapping courses, the entire buttlap portion of a subsequent course has headlap beneath it. This manner of installation prevents leakage to the roof deck where the lateral edges of the shingles abut each other.
In a typical roofing system, contiguous shingles in a row abut each other at their lateral edges. Thus, when the shingles are exposed to wet weather, it is possible that leakage can occur at the region where the shingles abut. To prevent that, overlapping subsequent rows of shingles are installed in an offset pattern and each shingle's headlap portion is at least as wide as the buttlap portion. Thus, when the shingles are applied to the roof in a plurality of courses and the buttlap portion of a second course of shingles is laid over the headlap portion of a first row of shingles there is always headlap present underneath the regions where the contiguous shingles in a row abut. Any water penetrating the places where lateral edges of shingles abut contacts the underlying headlap rather than the roof deck.
Asphalt shingles are among the most commonly used roofing materials. Asphalt shingles, such as those disclosed in U.S. Pat. No. 6,990,779, have been used extensively in residential housing as roof covering due to their aesthetics, ease of installation, water shedding function, and excellent field performance over a long period of time. U.S. Pat. No. 6,990,779 discloses a laminated roofing shingle system including a reduced-width headlap portion and an interply material that is installed under the buttlap portion in order to compensate for the reduced-width headlap portion and provide protection to the roof deck.
In some cases, prior art shingles may rely on redundant overlapping to ensure adequate water shedding performance, particularly in high wind or wind-driven rain conditions. For example, a typical prior art shingle know as a “3-tab shingle” would require approximately 240 ft2 of sheet material to cover a 100 ft2 of roof area (also known as a “square”). Other types of shingles also require significantly high amounts of overlapping materials to achieve adequate performance for resistance to water infiltration.
Single-layer strip shingles present a low cost roofing option, but presently available strip shingles are still more expensive than some consumers would like for homes, sheds, or other low cost buildings.
As energy costs rise, the cost of petroleum-based materials, such as asphalt, and transportation expenses often rise as well. The amount of material employed in a shingle can contribute to costs of the shingle and the overall weight of the shingle, which also affects transportation costs. Certain design requirements, such as a two inch or 2¼ inch material overlap from any point of water entry, constrain the possible dimensions for a shingle. Decreasing the amount of asphalt, substrate, and other materials required to make a shingle while maintaining the equivalent performance and coverage area can reduce both material costs and transportation expenses to deliver such shingles. Material costs (and transportation expenses) can be further reduced by maximizing the exposure (or coverage) of each individual shingle by requiring fewer shingles to cover a roof deck.
Various shingles have been developed that employ a shiplap or side-lap feature such that when applied to a roof deck at least part of the lateral edges of neighboring shingles overlap. U.S. Pat. No. 2,106,396 discloses single layer asphalt coated shingles having serrated edges having edge and corner elements. When the shingles are applied to a roof deck, their lateral edges overlap. The edge and corner elements of the shingles may be utilized as guides for laying the elements of each shingle in proper relation to each other in each course and also for properly relating the elements in one course to those in a subjacent course.
U.S. Pat. No. 2,272,032 describes single layer asphalt roofing shingles with varying cross-sectional thickness to be arranged in offset overlapping courses, wherein the side edge portions of adjacent shingles in the same course overlap. The shingle has longitudinal zigzag edge contours, which shadow each other on either side of the shingle such that the width of the shingle is constant across the length of the shingle. When the courses are installed, the thicker portions of a subsequent shingle “nest” in the thinner portions of the previously installed shingle to provide the protection qualities of more heavily coated roofing material.
U.S. Pat. No. 2,687,701 discloses single layer tabbed asbestos cement roofing shingles comprising projections on the front and rear edges. When the shingles are applied to a roof deck, their lateral edges overlap. The shingles comprise projections which extend above and over the buttlap portion of a previous course when a subsequent course is installed. The overlapping and projections are intended to create a more dimensional appearance.
U.S. Pat. No. 3,919,823 discloses single layer asphalt roofing shingles. The shingles comprise various projections on the front edge. The shingles are installed such that their lateral edges overlap to create what is described as a “shadow effect” which will vary depending on the time of day.
U.S. Pat. No. 4,274,243 discloses a laminated asphalt roofing shingle to be arranged in overlapping courses to optically simulate tiles. The shingle has a buttlap portion with curved tile-like features and the left-most tile-like feature includes an overlap portion that extends over the adjoining edge of a neighboring shingle to hide the adjoining edge between the shingles.
U.S. Pat. Nos. 4,333,279 and 4,527,374 disclose strip or tabbed single layer asphalt shingles. The shingles comprise various edges at least one of which is an alignment edge. The shingles are overlapped using the alignment edge in order to achieve a desired pattern when the shingles are installed on a roof deck.
U.S. Pat. Appl. Publ. No. 2004/0182032 discloses a multi-layer laminate shingle with a reduced-width headlap portion. The shingle has a base layer and at least a second layer above the base layer. At one end of the shingle the base layer projects beyond the second layer while at the other end the second layer projects beyond the base layer. When the shingles are laid in a course along the roof, the projecting end of the second layer overlaps the projecting end of the base layer of the previously installed shingle, forming a shiplap joint over all or substantially all of the width of the shingle.
U.S. Pat. Appl. Publ. No. 2011/0185668 discloses a laminated roofing shingle system including a reduced-width headlap portion, wherein the roofing system comprises a plurality of courses, and wherein a trailing edge of a subsequently installed shingle in a course overlaps the leading edge of an adjacent previously installed shingle in the same course.
In addition to certain of the shingles discussed above, various shingles have employed non-straight edge contours. U.S. Pat. No. 1,732,403 discloses a tabbed strip shingle and method of forming the shingle. The shingles are cut from a sheet of roofing material, wherein the front edge profile of the shingles are cut with a zigzag pattern to form complementary shingles. The tabs of the shingles are separated by parallel slots and have a generally triangular front edge with a small horizontal tip portion. When installed, the small horizontal tip portion of the tabs of shingles in a subsequently installed course align with the ends of the slots of shingles in a previously installed course. The shingles require approximately 225 ft2 of sheet material to cover a 100 ft2 of roof area.
U.S. Pat. No. 1,846,635 discloses a method of cutting so-called hexagonal strip shingles without waste from a parent sheet of prepared roofing. Each shingle has an exposed edge that defines projecting tongues having three sides of a hexagonal shape separated by recesses. When installed the projecting tongues match with the recesses of previously installed shingles, i.e., the projecting tongues have an end breadth equal to the breadth of the recesses in the buttlap. The shingles may also have a headlap with projections and recesses, wherein the end breadths of the headlap projections are equal to the headlap recesses and different from the tongue end breadths and buttlap recesses. U.S. Pat. No. 1,846,635 further discloses a formula for calculating the average exposed width of the shingle and that the shingle has a maximum width (“extreme width”) that is twice the average exposed width plus the desired overlap from a successively installed shingle.
U.S. Pat. Appl. Publ. No. 2003/0172611 discloses shingles having a headlap region and a visual feature region, wherein the visual feature region includes teeth and cutout spaces that are identical in shape and size, with respect to each other. When installed, an alternating pattern is achieved along a vertical line extending up the shingled roof between teeth and cutout spaces of the visual feature regions of overlapped, vertically adjacent shingles.
U.S. Pat. Appl. Publ. No. 2013/0160389 discloses shingles having a headlap portion with a non-straight longitudinal edge and a buttlap portion with a non-straight longitudinal edge, wherein the non-straight longitudinal edges do not shadow each other laterally across the shingle. U.S. Pat. Appl. Publ. No. 2013/0160389 further discloses a roofing system wherein at least a portion of the headlap portion of a shingle in a subsequently installed course overlaps at least a portion of the headlap portion of a shingle in a previously installed course and a maximum headlap overlap dimension is beneath the subsequently installed shingle laterally proximate the openings in the buttlap portion of the subsequently installed shingle. U.S. Pat. Appl. Publ. No. 2013/0160389 further discloses a method of making the shingles wherein the shingles are cut from a sheet of roofing material longitudinally along non-straight lines.
Each of the above-referenced patents and patent applications is incorporated herein by reference in their entirety for all purposes within this application.